The Importance of a High-quality MVHR System: Why Performance Matters More Than Product
Mechanical Ventilation with Heat Recovery (MVHR) is a crucial technology for maintaining optimal indoor air quality and comfort in airtight homes. Airtight homes are designed to conserve energy and with effective ventilation, improve the health and wellbeing of their occupants.
When designed correctly MVHR provides such a ventilation solution, ensuring the correct airflow and enhanced indoor air quality, while supporting the overall health of the building’s occupants and the fabric of the building. Importantly, a well-designed system will minimise heat loss through is ability to recover heat from the exhaust air, and operate quietly—so quietly, in fact, that it should be inaudible.
Box-ticking vs. Performance: Two Approaches to MVHR
There are two primary markets for MVHR systems. The first involves installations where a ventilation system is required purely to meet Part F in building regulations. This is effectively a "box-ticking" exercise and almost always a missed opportunity. The second is where a high-quality system is chosen to ensure optimal health and comfort for the occupants, protect the building fabric, and maximise heat recovery for better energy efficiency. While it’s possible to opt for a system just to satisfy the Part F paperwork, investing in a high-performance MVHR system can deliver long-term benefits by reducing energy bills and enhancing comfort. So why not choose a solution that does more than just meet the minimum standard?
The Pitfalls of Poor Design
As MVHR increases in popularity, so too does the number of inadequate services and systems on the market. Unfortunately, when systems fail, 95% of the time the issue can be traced back to either the lack of good design or a poorly executed one. Often, these designs are simply schematics showing where the ducts should be placed, without addressing the key aspects of performance.
What Truly Defines a High-performance MVHR System
There are two key aspects to the performance from an MVHR system, the first is flow rate the second is decibel rating, how loud the system is – not the unit the whole system. One of the biggest mistakes is focusing on a specific product specification rather than a performance specification. It’s not uncommon to see requirements like "an MVHR unit from manufacturer A must be provided." However, the focus should be on the system's performance, with the flexibility to choose the right products to meet that goal. For example, instead of specifying a brand, you might say: "The MVHR system must deliver 30m³/hr per person, ensure sound levels in habitable spaces do not exceed 25dB(A), keep total static pressure under 100Pa, and ensure air diffusers are positioned for optimal airflow." And crucially, this performance should be backed by an indemnified design agreement.
How 21 Degrees Delivers Dependable MVHR Performance
At 21 Degrees, our MVHR design service guarantees that your MVHR system is not only inaudible but also delivers the necessary airflow for health, comfort, and efficiency—all while keeping running costs low thanks to our low-pressure ducting design. After supplying the products to match the specification, we commission the system on-site to ensure it performs as designed, eliminating the performance gap that often occurs with poorly installed systems.
Final Thought: Design First, Brand Second
The key takeaway? Always prioritise a performance specification over a product specification. The effectiveness of your MVHR system is determined not by the brand of the unit but by the quality of the ducting design and how efficiently air moves through the system. The MVHR unit can only perform as well as the duct system it is connected to, so the design and installation process is critical to achieving the best results.
If you would like to know more about how we can provide you with the best MVHR installation, contact 21 Degrees today.
